Mega users: If you're hacked once, you're hacked for life

Mega users: If you're hacked once, you're hacked for life

Summary: Pessimists, or perhaps realists, in the security industry say that being hacked is a matter of when, not if. But if you're a Mega user, do whatever you can to make sure you're never hacked, because you can't change your password and you can't delete your account.


Kim Dotcom's launch of Mega has touted the big tagline of being bigger, better, faster, stronger, and safer, but while Dotcom promises 128 bits of AES encryption and the use of 2048 bits of RSA public/private key infrastructure, I'm not too convinced about the last aspect of his sell: the safety.

Mega's security operates in a different way to a lot of other sites. Its use of public/private pair keys is a good step for ensuring that no one but the owner of the private key pair has the ability to decrypt files that are stored in its cloud service, but it appears to also be tied into the password used to set up the account.

If you're a Mega user, do whatever you can to make sure you're never hacked, because you can't change your password and you can't delete your account. Image: Mega

Mega's site states that it is "the master encryption key to all of your data" and that "if you lose it, you lose access to all of your files that are not in a shared folder and that you have no previously exported file or folder key for." However, tying the password deeply into the encryption scheme also means that it is impossible to reset or change a user's password without throwing away the encryption keys. Combined with the current inability for users to close their account and create a new one, and users are stuck with whatever password they signed up with. Hopefully, that wasn't "password," while they figured out whether they wanted to keep using the service.

And hopefully they didn't typo it, either, because Mega doesn't ask users to type their password again to confirm during the sign-up process.

But, more importantly, this approach to security highlights something that is more important than the strength of keys and passwords: the ability to revoke and issue new ones.

Previous security incidents have left organisations urging their users to reset their passwords, even when the targeted organisation was not affected. An example of this is the recent case of a New Zealand bank that claimed its site was being cloned for another payment processor's site. The incident did not involve the bank's own infrastructure — its systems were never breached — but the only advice it could really give its customers was for them to change their passwords. In Mega's case, this would be impossible.

In the event of a phishing campaign or malware that specifically targets the farming of users' Mega passwords, users don't have any options available to them to improve their security. Mega isn't responsible for the security of its users' PCs, or their behaviour on any unsavoury websites.

And if an account is compromised, what then? Attackers could have a laugh, uploading pornography randomly into users' documents; be downright malicious and delete all of their files in an instant; or, possibly worse, download them all to snoop through.

A vigilant user might discover that their account is being accessed from another browser at another IP address, but there are no options to disconnect the user and ban that address. Even if there were, the attacker could just use a proxy to change their IP address, log in with the same password again, and even employ the same futile lockout method on the original owner. Against a less tech-savvy user, perhaps it might even work.

So, sadly, the only thing that the account holder can do is delete their own files before their adversary can download them — a humiliating defeat, but the only way that they can protect their files, because, once hacked, they're hacked forever. Which leads me to question the point of having individual accounts in the first place. With this amount of security, the only files worth putting up are those that are only temporary or are going to be shared publicly anyway, both of which can be achieved through anonymous accounts.

But if we give Mega the giant assumption that all of its users will use long, unique passwords, and won't fall victim to phishing schemes or keyloggers and the like, their own systems should be fairly secure, right?

Not quite.

Users have already found cross-site scripting vulnerabilities on the site, which could be used, for example, to send off session cookies to an attacker so that they can log in as they please. Someone with a more malicious imagination can come up with better, but I can easily see the potential for a social engineer to create a form that requires the user to log in again before they can upload or download files. From here, they could gather Mega log-in details or even request that the user "link" accounts with other services, such as Facebook, or PayPal, if they're daring enough.

Unless things change in the future, and passwords are not tied so intimately to the encryption keys forming the basis for Mega's security, the alternatives will, at best, be a workaround. If Mega eventually allows accounts to be erased and closed, the paranoid (or those who are serious about security — it's a tough call to make a distinction) may opt to completely remove all of their content and sign up again just to change their password. With free accounts providing up to 50GB of cloud storage, many won't have the time and bandwidth to go through the hassle.

There will no doubt be various uses for Mega, such as uploading content that is meant to be publicly accessible and shared, but, if you were thinking about using it as a nice way to provide even more redundant storage for your documents and family photos, I'd steer clear for a while yet.

It's hard to say when Mega might become secure enough for more personal content, but it doesn't look like it will be soon; there are a number of enhancements coming up for the cloud storage site, but security barely rates a mention on the list of "essentials."

Topics: Security, Cloud, Storage, New Zealand

Michael Lee

About Michael Lee

A Sydney, Australia-based journalist, Michael Lee covers a gamut of news in the technology space including information security, state Government initiatives, and local startups.

Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.


Log in or register to join the discussion
  • The author exaggerates

    I am sensing a bit of exaggeration here, taking into account the site just launched yesterday and it is still showing a -quite noticeable- beta tag (which is not mentioned in your article).
    • I agree, its still too early to see what is going to happen

      I agree, its still too early to see what is going to happen. Hopefully we can see this site mature without "intervention".
  • I've already ran into an issue

    Where the site is telling me that I am not putting in the correct password.... even though I copy&pasted the password into the website both for the initial input when signing up and when I was trying to sign in.
    • Here also

      I get either Bad Password or Bad registration credentials (-9) and them I am logged in.

  • Worse News

    Your Mega account is compromised when you register. The confirmation link contains a hash of your password. I'll be releasing "MegaCracker" hopefully in a few hours
    • Very bad indeed

      If Mega has possession of a hash of your login password, they're only a few CPU cycles away from having your actual password itself, at least if they've used any general purpose hash function. Almost any password can be brute-force cracked given its hash function quite quickly.

      If you look at what they're stating about their security model, it's that "this master key is stored on MEGA's servers, encrypted with a hash derived from the user's login password."

      So actually Mega themselves - or anybody who confiscates their servers - or even just presents a demand for the encrypted data associated with a particular user - could likely decipher that user's file locker without too much difficulty.
  • E-mail

    I created a new e-mail address to use for my registration. So I can delete my content and move on to the next e-mail if I want.
  • Password Change

    The story oversimplified MEGA's security (More info here

    "If you're hacked once, you're hacked for life" is an overstatement. If a hacker hacks your account, they could get access to all of your data, regardless of service. But you _COULD_ change your password. Nothing in the cryptography that MEGA is using will prevent you from changing your password. Their beta site just does not support it _yet_. (Just don't forget your password, then your really are screwed for life)

    If you change your password _AFTER_ you were hacked, you would need to reupload everything to use new keys. But only if you were hacked, not for a regular password change.
    • Title is misleading

      "If you're hacked once, you're hacked for life" is plain wrong. if you go read Mega's website. They say that will allow you to change your password, at which point the old password will not work. They haven't provided that feature yet, but they're saying that they will. The author should give them some credit - they aren't nincompoops.
  • Master Encryption Key ≠ Password

    Just a note that you don't supply your master encryption key when you login, only your password. That is then used to decrypt the master encryption key, which is kept on the server (presumably never saved in decrypted form). So changing your password simply involves decrypting the master encryption key, then encrypting it with the new password. You as the user never need to see the master encryption key again, after you have generated it.

    At least, that's how I understand it.
  • I don't get the drama

    was anyone going to trust something sensible and/or worth big $$$ to a FREE online storage service anyway?? not without putting it into archive with your own strong password
  • Pirates, double encryption and/or file splitting

    The whole article is puzzling. The author never mentions the REAL reason the encryption is there, which is to push responsibility for any piracy completely out of Mega's control. This was easy to see years ago - pirates will simply share links INTO Mega, rather than sharing pirate files themselves, and Mega will be innocent. (And will be glad to take down encrypted files- which they don't know what they are anyway- anytime the FBI fingers them - one by one.) IOW, the password can be "password" for the pirated movies you just uploaded, since the whole point is cross-sharing of pirated files.

    Do you actually want to keep data safe on Mega? Why not split sensitive files, encrypt the pieces yourself and store them in different Mega accounts, or choose different cloud providers for each piece? Writing a Perl script shouldn't be too hard to automate the entire process, and you could use a Linux VM run entirely in memory to view or work with the files (meaning the unencrypted data never touches persistent memory). If doing all this isn't good enough, try Truecrypt, and send the "blank" SD cards holding the files to an anonymous mail drop.

    If that won't work, your issues go way beyond security concerns. ;)
  • I Can't Be The Only One

    C'mon. I can't be the only one who doesn't trust Kim Dotcom. He was shady to begin with. Shunned authorities. Flaunted his 'untouchability.'

    I wouldn't trust his service with any important files or any other service that bares his name. Seems that he's, again, launching Mega as a EFF YOU to the authorities albeit with a more defined ToS to indemnify him for future legal problems.
    • Who would you trust though?

      You say you wouldn't trust Dotcom. Who do you trust with your data then? Google? Microsoft? Yahoo? Dropbox? Amazon? Half of those will gladly sell your most private info to the highest bidder, and the other half will give it up to government(s) so fast, you won't even have time to say "MAFIAA."